Abstract
Three major new technologies developed in the past decade in the heavy oil regions of Alberta and Saskatchewan are long, shallow horizontal wells, Steam-Assisted Gravity Drainage (SAGD), and Cold Production (CP). These three technologies are briefly reviewed. They can be combined in a general approach to heavy oil reservoir development that will give the advantages of reasonable early oil production rates, continued long-term production, and excellent long-term recovery.
A combination of vertical wells and horizontal wells are used to achieve early CP, which is then gradually replaced by long-term SAGD production. As the processes progress, vertical CP wells will decline in production rate; when they are no longer economical to produce, these wells are converted to other purposes. They can be used as inert gas injectors, control wells, low-rate thermal injection or production wells, or even sand disposal wells, as long as they help maintain the reservoir at the appropriate pressure for SAGD. The proper balance of pressures through injection or production to maintain the long-term stability of processes in the gravity-dominated flow regime is critical to SAGD success.
Given price fluctuations and long-term projections, economic factors related to heavy oil must be addressed. It is appropriate to point out that within 10-15 years, the current conditions of low prices and over-supply of conventional crude oil will be replaced by a world-wide shortfall in oil supply, which should bring a permanent increase in oil prices.
This suggests that corporations should be making substantial investments in heavy oil at the present time.
